Abstract: A ball-and-socket joint comprising: a housing having an open end at its upper end, the upper end having an inner peripheral surface which inclines upward and radially inward; a bearing element disposed in the housing; a ball stud having a ball end retained in the bearing element and a shank portion extending from the ball end freely through the open end of the housing; an end cover plate secured in a lower end of the housing; and a resiliently yieldable member compressed between the bearing element and the end cover plate for urging the bearing element against the ball end of the ball stud. The inner peripheral surface of the housing is locally hardened by a high frequency hardening.

Abstract: A tulip-shaped metal part such as a yoke component of a tri-port type constant velocity universal joint is manufactured by single-stage closed chamber extrusion of a solid cylindrical metal rod. The metal rod is inserted into two opposingly engaged dies to protrude into a space defined in the dies and is axially pressed against an impressed surface to cause gradual and continuous cleavage of the rod into three branched portions, which are forced into three chambers arranged and shaped like three petal-like arms of the desired tulip-shaped metal part. The branched portions of the metal material are extruded within the three chambers in directions parallel to the direction of the pressing force exerted on the metal rod, with continued application of a back pressure in opposition to the extruded portions of the metal material to shape the ends of the petal-like arms during the extrusion process.